Method method

lib/internal/test_runner/mock/mock.js:473–550

* Creates a method tracker for a specified object or function. * @param {(object | Function)} objectOrFunction - The object or function containing the method to be tracked. * @param {string} methodName - The name of the method to be tracked. * @param {Function} [implementation] - An optiona

(
    objectOrFunction,
    methodName,
    implementation = kDefaultFunction,
    options = kEmptyObject,
  )

   * @returns {ProxyConstructor} The mock method tracker.
   */
  method(
    objectOrFunction,
    methodName,
    implementation = kDefaultFunction,
    options = kEmptyObject,
  ) {
    validateStringOrSymbol(methodName, 'methodName');
    if (typeof objectOrFunction !== 'function') {
      validateObject(objectOrFunction, 'object');
    }

    if (implementation !== null && typeof implementation === 'object') {
      options = implementation;
      implementation = kDefaultFunction;
    }

    validateFunction(implementation, 'implementation');
    validateObject(options, 'options');

    const {
      getter = false,
      setter = false,
      times = Infinity,
    } = options;

    validateBoolean(getter, 'options.getter');
    validateBoolean(setter, 'options.setter');
    validateTimes(times, 'options.times');

    if (setter && getter) {
      throw new ERR_INVALID_ARG_VALUE(
        'options.setter', setter, "cannot be used with 'options.getter'",
      );
    }
    const descriptor = findMethodOnPrototypeChain(objectOrFunction, methodName);

    let original;

    if (getter) {
      original = descriptor?.get;
    } else if (setter) {
      original = descriptor?.set;
    } else {
      original = descriptor?.value;
    }

    if (typeof original !== 'function') {
      throw new ERR_INVALID_ARG_VALUE(
        'methodName', original, 'must be a method',
      );
    }

    const restore = { __proto__: null, descriptor, object: objectOrFunction, methodName };
    const impl = implementation === kDefaultFunction ?
      original : implementation;
    const ctx = new MockFunctionContext(impl, restore, times);
    const mock = this.#setupMock(ctx, original);
    const mockDescriptor = {